Method for assessing the tread condition of vehicle tires, taking microstructure into account

Abstract

The invention relates to a method for evaluating the tread condition of vehicle tires (10), comprising an electronic condition assessment device (12) comprising an electronic data processing device (14) with a storage unit (16), comprising the method steps: a) acquiring a first graphical representation of the macroscopic surface condition for at least a first tread section (18) of the vehicle tire (10) with a first detection unit (20) of the condition assessment device (12), wherein the first detection unit (20) uses an optical detection method, b) acquiring a second graphical representation of the microscopic surface condition for at least a second tread section (22) of the vehicle tire (10) with a second detection unit (24) of the condition assessment device (12) that is different from the first detection unit (20).wherein the second detection unit (24) uses an acoustic detection method, and c) evaluating the profile condition of the vehicle tire (10) by evaluating the first graphical representation and the second graphical representation with the electronic data processing device (14) to obtain condition information.

Description

[0001] The invention relates to a method for evaluating the profile condition of vehicle tires and a condition evaluation device for use in the corresponding method.

[0002] In light of the steady increase in global road traffic and the associated rise in traffic accidents, driving safety has become increasingly important in recent years. One vehicle component that plays a crucial role in driving safety is the tires, which are specifically designed to suit expected environmental conditions in order to optimize handling and braking performance.

[0003] Besides the type of rubber compound used, the tire tread pattern is of particular importance with regard to the driving safety characteristics of vehicle tires, as its structure significantly influences handling and braking performance. However, vehicle tires wear down over time, with the tread pattern and its specific structure gradually eroding. Given the high safety relevance of a sufficiently pronounced tread pattern, many countries have strict regulations regarding minimum tread depths.

[0004] In many countries, vehicle owners are required to regularly check the remaining tread depth and overall condition of their tires. In practice, this is often done using very simple tests with a ruler or similar reference points, with the general condition assessment frequently limited to a purely visual inspection.

[0005] To improve the often unreliable manual assessment of vehicle tire condition, various (semi-)automated methods for evaluating the tread condition of vehicle tires have been proposed in the prior art, including those proposed by the inventors of the present invention. These methods generally rely on determining, or at least reliably estimating, the remaining tread depth and any existing wear phenomena, such as uneven wear, using detection methods, particularly non-contact detection methods, in order to then assess the tread condition of the vehicle tires. Many of the methods proposed in the prior art prove to be relatively efficient in measuring the macroscopic tread structure of the vehicle tires and determining the remaining tread depth.

[0006] In the course of developing improved methods for assessing the tread condition of vehicle tires, the inventors recognized that while the prior art's focus on the macroscopic structure of the tires already provides valuable information in many respects, there are also other factors influencing the actual tread condition of the vehicle tire that these methods cannot adequately account for. Furthermore, it was found that optical detection methods for capturing the macroscopic tread structure are sometimes limited in their accuracy because the measurement conditions at the moment of acquisition are inadequate, for example, due to poor lighting conditions, resulting in an inaccurate assessment of the tread condition.

[0007] The primary objective of the present invention was to eliminate or at least reduce the disadvantages of the prior art.

[0008] In particular, the object of the present invention was to provide an improved method for evaluating the tread condition of vehicle tires, with which a more precise and accurate evaluation of the tread condition of vehicle tires should be possible.

[0009] It was an object of the present invention that the specified method should make it possible to capture particularly detailed information about various aspects relevant to driving safety and durability, going beyond the mere evaluation of the macroscopic structure of the vehicle tires.

[0010] Furthermore, it was another objective of the present invention that the specified method for evaluating the profile condition should be more robust and executable with higher reliability, with particular aim of reducing the dependence on the measurement conditions, especially good lighting conditions.

[0011] A further objective of the present invention was to ensure that the specified method could be carried out with as much process reliability as possible and that it would enable even inexperienced users to make a reliable assessment of the profile condition with as little guidance as possible.

[0012] Likewise, a further objective of the present invention was that the specified method should place as few demands as possible on the use of specialized equipment, and it was a desirable requirement that the specified method should be feasible as far as possible with equipment that many end users already have available.

[0013] Building on this, a further object of the present invention was to provide an advantageous condition assessment device for use in the specified method.

[0014] The inventors of the present invention have now found that the problems described above can be solved by using a method for evaluating the profile condition in which, in addition to detecting a first graphic representation of a profile section by means of an optical detection method, which depicts its macroscopic structure, a second graphic representation of the microscopic surface condition is also captured by means of an acoustic detection method, either in the same or a different profile section of the vehicle tire, and the evaluation of the profile condition of the vehicle tire is carried out by evaluating both this first and the second graphic representation, as defined in the claims.

[0015] Advantageously, this makes it possible to compensate for any shortcomings in the detection of the first graphical representation by means of the complementary second, acoustic method, thereby increasing the reliability and robustness of the method according to the invention and, in particular, reducing its dependence on optimal measurement conditions, especially favorable lighting conditions. Furthermore, the use of an additional acoustic detection method advantageously makes it possible to obtain information about the microstructure of the rubber material in the tread section, in addition to the macroscopic surface properties, for example, with regard to the remaining tread depth, which has an important influence on the driving safety characteristics of the vehicle tire.According to the inventors, this microscopic surface texture, which can manifest itself, for example, through unevenness, cracks or other microscopic damage, has a significant influence on the driving safety properties of the vehicle tire as well as on the general durability forecast of the vehicle tires.

[0016] Advantageously, the method according to the invention can be integrated with relatively little programming effort into many modern mobile devices, for example mobile phones or tablets, via a suitable computer program product, which are thereby enabled to provide a particularly reliable and detailed assessment of the profile condition of vehicle tires.

[0017] The aforementioned problems are thus solved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention are described in the dependent claims and the following descriptions.

[0018] Such embodiments, which are hereinafter referred to as preferred, are combined in particularly preferred embodiments with features of other embodiments also referred to as preferred. Combinations of two or more of the embodiments hereinafter referred to as particularly preferred are therefore especially preferred. Also preferred are embodiments in which a feature of one embodiment, referred to as preferred to any degree, is combined with one or more further features of other embodiments, which are referred to as preferred to any degree. Features of preferred condition assessment devices result from the features of preferred methods.

[0019] Particularly preferred embodiments of the invention are disclosed in the exemplary embodiments. Particularly preferred embodiments of the invention have two or more, preferably three or more, and most preferably four or more, of the preferred features of the invention disclosed below, which are also implemented in the exemplary embodiments.

[0020] The invention relates to a method for evaluating the profile condition of vehicle tires, with an electronic condition evaluation device, comprising an electronic data processing device with a storage unit, comprising the method steps: a) Capturing a first graphical representation of the macroscopic surface texture for at least a first profile section of the vehicle tire with a first detection unit of the condition assessment device, wherein the first detection unit uses an optical detection method, b) Capturing a second graphical representation of the microscopic surface texture for at least a second profile section of the vehicle tire using a second detection unit of the condition assessment device that is different from the first detection unit, wherein the second detection unit uses an acoustic detection method, and c) Evaluating the profile condition of the vehicle tire by evaluating the first graphical representation and the second graphical representation with the electronic data processing device to obtain condition information.

[0021] The method according to the invention serves to evaluate the tread condition of vehicle tires. In accordance with the expectations of those skilled in the art, the result of such a method is condition information about the tread condition of the examined vehicle tire, which is derived by the electronic data processing device on the basis of detected graphical representations, optionally in combination with other influencing factors, using predefined evaluation criteria and / or machine learning-based approaches, wherein the condition information thus obtained can subsequently be used further, for example as input parameters in subsequent computer-implemented methods or by output as information to drivers or the fleet management system.

[0022] The method according to the invention is, in principle, suitable for determining the tread condition of all vehicle tires, provided they have a tread pattern that can be evaluated. For most cases, a method according to the invention is relevant in which the vehicle tire is a pneumatic tire or a deflated tire, preferably a pneumatic tire. By way of example, an additional or alternative method according to the invention is also relevant in which the vehicle tire is a truck or passenger car tire, preferably a passenger car tire.

[0023] The method according to the invention is carried out with the aid of a condition assessment device. This condition assessment device comprises a data processing device and a storage unit, wherein the data processing device can be used in accordance with the skilled person's understanding in the implementation of method steps a) to c).

[0024] It can be seen as an advantage of the method according to the invention that the condition assessment device can, in principle, be implemented in very different ways. According to the inventors, the method according to the invention is particularly well suited to enabling the end customer and vehicle owner to reliably assess the state of wear, in which case the condition assessment device can be formed, in particular, by electronic devices that are already available to the end user. A preferred method according to the invention is one in which the electronic condition assessment device is a portable device, preferably a mobile electronic device, and most preferably a mobile phone or a tablet.

[0025] The method according to the invention comprises three steps a) to c), each performed by a specific unit of the condition assessment device. Those skilled in the art understand that these units are each specifically configured to perform the respective method step, but that there are several possibilities regarding the precise design of each unit, from which the skilled in the art can choose, provided that these enable the necessary functionality. The units used in method steps a) and b), i.e., the first detection unit and the second detection unit, in any case allow interaction with the environment and comprise physical components, as disclosed below, which, however, in practice also interact with the data processing device because, for example, they are controlled by it.The person skilled in the art understands that, in contrast, the evaluation in process step c) will be carried out by a computer program product or a comparable algorithm that is executed on the data processing device.

[0026] In process step a) of the method according to the invention, a first graphic representation of the macroscopic surface texture is detected for at least a first profile section of the vehicle tire. This wording expresses that a graphic representation of the macroscopic surface texture is to be captured, for example, because this can be derived from the measured values ​​of the first detection unit using a suitable program. Even if it would theoretically be conceivable to make two-dimensional graphics sufficiently informative, for example, by using suitable shading, so that they include information about the macroscopic surface texture, the inventors believe that for essentially all embodiments, it is preferable to capture a three-dimensional structure.A preferred method according to the invention is therefore one in which the first graphical representation of the macroscopic surface texture is a three-dimensional representation of the macroscopic surface texture.

[0027] Within the scope of the present invention, a distinction is made between a macroscopic and a microscopic surface texture. Reference can be made to the general understanding of those skilled in the art. In principle, macroscopic surface textures are those that are readily visible to the naked eye from a certain distance from the vehicle tire. In the case of tire treads, this means in particular the tread structure of the vehicle tire, i.e., the entirety of tread grooves and tread blocks, optionally with macroscopic structuring elements. A preferred method according to the invention is therefore one in which the macroscopic surface texture comprises the tread structure in the first tread section, in particular the tread blocks separated by tread grooves.

[0028] To clearly distinguish macroscopic elements, the inventors propose that this can also be defined by the resolution of detectable structural elements. Specifically, a method according to the invention is preferred in which the first graphical representation of macroscopic surface features structural elements with a dimension of 5 mm or more, preferably 10 mm or more, and particularly preferably 15 mm or more.

[0029] According to the invention, the first graphic representation is captured by a first detection unit. This unit, according to the invention, relies on an optical detection method. In principle, all optical detection methods known to those skilled in the art can be used, for example, 3D scanners based on electromagnetic radiation. However, in the inventors' opinion, the use of camera-based methods is particularly well suited for capturing the desired graphic representation. Macroscopic structural elements can regularly be clearly identified in corresponding images, even with simple image acquisition methods.Furthermore, additional depth information can be obtained using optical image acquisition techniques that are generally known to those skilled in the art. This allows for the calculation of a three-dimensional graphic representation, for example, by using two or more cameras and / or multiple light sources that enable the calculation of the three-dimensional structure from different viewing angles and / or different lighting conditions. This is therefore a method according to the invention, wherein the acquisition of a first graphic representation of the macroscopic surface structure comprises generating an image using the optical detection method.A preferred method according to the invention comprises the first detection unit comprising an optical image acquisition device or an electromagnetic radiation-based 3D scanner, preferably an optical image acquisition device, particularly preferably a camera, particularly preferably a 3D camera.

[0030] To reduce the required computing power and improve the quality and reliability of the resulting macroscopic surface texture, the inventors propose, in particular, the use of projection devices to project, for example, a grid of lines or luminous points onto the vehicle tire. The distortion of the pattern thus applied to the tire enables easier and more reliable identification of the surface information. A further advantage of this design is that many modern electronic devices, such as mobile phones, contain comparable projection devices that, for example, support or enable facial recognition.The person skilled in the art understands that the electromagnetic radiation used for the projection does not necessarily have to be in the visible light range, but can also be in the IR range, for example, provided that the first detection unit used is able to perceive the structures projected onto the vehicle tires or their image on the profile.A preferred method according to the invention is therefore one in which the first detection unit comprises an optical image acquisition device and a projection device configured to project a pattern onto the first tread section of the vehicle tire, and the electronic data processing device is configured to calculate a three-dimensional image and / or a topographic representation of the first tread section of the vehicle tire as a first graphic representation of the macroscopic surface texture from the image of the pattern detected by the first detection unit on the first tread section of the vehicle tire. A method according to the invention in which the pattern is projected in the form of a grid or raster is particularly preferred.Particularly preferred is also or alternatively a method according to the invention in which the projection device is configured to project the pattern onto the profile section of the vehicle tire by means of IR radiation.

[0031] In process step b), a second graphic representation is captured in addition to the first. This second representation focuses on the microscopic surface texture, which is captured in a second profile section. While the inventors consider a three-dimensional representation preferable for the first graphic representation, they believe that two-dimensional representations, such as images, can be used efficiently for the second graphic representation of the microscopic surface texture, provided these representations convey relevant information about the surface texture through height information.A preferred method according to the invention is therefore one in which the second graphic representation of the microscopic surface texture is a two-dimensional representation of the microscopic surface texture, preferably a two-dimensional representation in which height information is recognizable via contained color information, preferably via grayscale levels.

[0032] The aim of recording the microscopic surface texture is, in particular, to detect the microscopic surface roughness and the presence of microscopic cracks in the second tread section, since, in the inventors' opinion, these are particularly relevant for the driving characteristics of the vehicle tire and also advantageously allow conclusions to be drawn about the expected durability of the vehicle tires. A preferred method according to the invention is one in which the microscopic surface texture comprises the surface roughness and / or microcracks in the second tread section.

[0033] Analogous to the preceding approach of defining the macroscopic surface texture via the structural elements recognizable in the graphic representation, the inventors propose that this can also be implemented analogously for the microscopic surface texture for clear differentiation, with the corresponding features naturally being preferably defined for both the microscopic and macroscopic surface textures. A preferred method according to the invention is thus one in which the second graphic representation of the microscopic surface texture reveals structural elements with a dimension of 0.5 mm or less, preferably 0.1 mm or less, and particularly preferably 0.05 mm or less.

[0034] The above definition defines the first graphical representation of the macroscopic surface texture as being detected in a first profile section, and the second graphical representation of the microscopic surface texture as being detected in a second profile section. This definition implies that the first and second profile sections can be fundamentally different, even if they are profile sections of the same vehicle tire. In practice, this can occur particularly because the user does not align the different detection units with the exact same profile sections.Advantageously, thanks to the often relatively uniform loading of vehicle tires across their circumference, the inventors believe it is not overly significant if the macroscopic and microscopic structures are determined at different points around the circumference of the tire or at different points along the tread width, as a very advantageous and informative assessment of the tread condition can still be achieved. The inventors also believe that the second tread section, in which the second graphic representation is captured, will often be smaller than the first due to the acoustic detection methods used, as camera-based methods, in particular, can easily capture very large tread sections simultaneously.For many cases, a method according to the invention is particularly relevant for application, wherein the second profile section is the same size as or smaller than the first profile section.

[0035] According to the inventors, obtaining particularly informative condition data is preferable if the first and second profile sections are superimposed as much as possible, so that the second graphical representation allows conclusions to be drawn about the microscopic surface properties in at least a part of the first profile section, for which information about the macroscopic surface properties is also available. A preferred method according to the invention is therefore one in which the second profile section is at least partially, and preferably completely, encompassed by the first profile section.

[0036] According to the invention, the second graphic representation is acquired using an acoustic detection method. In practice, this will usually involve a method according to the invention, wherein the acquisition of the second graphic representation of the microscopic surface structure comprises generating a graphic image from the signals acquired by the acoustic detection method.

[0037] In the inventors' experiments, the use of ultrasound-based methods proved particularly advantageous for reliably and cost-effectively capturing the microscopic surface structure in the corresponding second profile section. A particular advantage here is that many modern mobile devices, such as tablets or mobile phones, incorporate corresponding ultrasonic sensors. These ultrasonic sensors are used in many modern mobile devices, for example, to capture fingerprints for unlocking the devices.It can be considered a great advantage that this sensor technology, which is present in many modern mobile devices alongside conventional cameras, can be repurposed for the present invention to determine the microscopic surface texture of vehicle tires by means of control via a suitable computer program. A preferred method according to the invention is therefore one in which the second detection unit comprises an ultrasonic sensor, and / or in which the acoustic detection method is an ultrasonic-based detection method.

[0038] According to the inventors, the acoustic detection methods used in process step b) will in many cases have a relatively short range compared to the optical detection methods of the first detection unit. In practice, this could mean, for example, that the first graphic representation of the first profile section is captured with the camera of a mobile phone, whereupon the corresponding mobile phone with its integrated ultrasonic sensor is placed on a part of the first profile section, which then forms the second profile section, in order to determine the microscopic surface properties with the mobile phone placed on it.To improve the detection quality, measuring fluids can be used, in particular gel-like measuring fluids, with which the surface of the tire tread can be locally wetted and which promote the execution of the ultrasound-based detection, as is known, for example, from other fields of technology, such as in the medical field. A preferred method according to the invention is therefore one in which the electronic condition assessment device directly or indirectly contacts the second tread section in process step b), and / or in which the electronic condition assessment device places the second tread section onto the second tread face in process step b).A method according to the invention is particularly preferred in which the electronic condition assessment device contacts the second profile section in process step b) via a measuring fluid, preferably a measuring gel, in particular an ultrasound gel.

[0039] In process step c), the profile condition of the vehicle tire is now evaluated. This is done by evaluating the first graphic representation and the second graphic representation, so that information about both the macroscopic and microscopic surface properties is included in the evaluation.

[0040] Within the scope of the present invention, the result of this evaluation is abstractly referred to as condition information. The skilled person can adapt the type and extent of the profile condition evaluation to the precise nature of the respective captured graphic representation and the desired information content that the skilled person wishes to derive from it. For example, it is possible to read the profile depth from the macroscopic surface texture using relatively simple image analysis, while the mean roughness value and / or the mean gap width of microcracks can be derived from the microscopic surface texture.For example, a method according to the invention is conceivable in which the evaluation of the profile state is carried out by evaluating the first graphic representation and the second graphic representation by comparison with historical first graphic representation and historical second graphic representation, preferably by differentiation.

[0041] Despite the fundamental suitability of even simple evaluation methods, the inventors consider it particularly preferable to use machine learning to evaluate the respective graphical representations together. Advantageously, it is possible to train an evaluation module using machine learning, which, after input of the corresponding graphical representation, evaluates the profile state and derives corresponding state information. A preferred method according to the invention is therefore one in which a machine learning-based evaluation module is stored on the storage unit, and the electronic data processing device is configured to...to input the captured first graphical representation and the captured second graphical representation as input into the evaluation module and to evaluate the profile state based on the captured first graphical representation and the captured second graphical representation, wherein the evaluation module is trained to evaluate the profile state from graphical representations of the macroscopic surface texture, which were captured using an optical detection method, and graphical representations of the microscopic surface texture, which were captured using an acoustic detection method, wherein the training is carried out with a set of training data which comprises a large number of graphical representations of the macroscopic surface texture, which were captured using an optical detection method, and graphical representations of the microscopic surface texture.which were detected using an acoustic detection method, included training vehicle tires with different, known tread conditions.

[0042] The concept of machine learning itself is known to those skilled in the art. Suitable computer programs, which can be adapted to the needs of the method according to the invention by appropriate training in light of the preceding disclosure, are commercially available from numerous vendors today or can be programmed to the respective requirements by appropriate service providers. An exemplary method according to the invention is one in which the evaluation module is based on a machine learning algorithm selected from the group consisting of supervised learning algorithms, preferably selected from the group consisting of logistic regression, support vector machines, K-nearest neighbors methods, decision tree methods, and artificial neural networks, and particularly preferably selected from the group consisting of artificial neural networks.

[0043] The person skilled in the art understands that the quality of the tread condition assessment obtained by machine learning will depend significantly on the training performed and the underlying training data. A key advantage of the method according to the invention is that the corresponding training set is particularly easy for the person skilled in the art to obtain. In practice, both new tires and tires in various states of wear represent a virtually unlimited resource. Using a suitable condition assessment device, in particular a condition assessment device such as the one used in the later method according to the invention, the person skilled in the art can acquire the necessary first and second graphical representations from these tires and link them to their condition assessment for the tread condition, which may, for example, be based on a professional's judgment.

[0044] The person skilled in the art understands that the efficiency of the training is significantly influenced by the fact that the information used for the training, i.e., the graphical representations, correlate as closely as possible between the training and the subsequent application. Accordingly, with regard to the efficiency of the training, it is preferred for essentially all embodiments if the graphical representations contained in the training data are each acquired using the same optical or acoustic detection method, and particularly preferably using the same state evaluation device.

[0045] The inventors suggest that the time and cost efficiency of the training, as well as the resulting evaluation accuracy, can be improved by optimizing the evaluation module for specific vehicle tires through more targeted training. A virtually unlimited number of boundary conditions are available to the person skilled in the art, allowing the evaluation module to be optimized for specific applications. This results in better predictive quality with less training effort in the desired range, which is generally advantageous, even if the evaluation quality may suffer outside these predefined ranges. For example, in later practice, it will regularly be efficient to specialize the corresponding evaluation module for a specific type of vehicle tire, such as commercial vehicle tires.Alternatively, it will be economically attractive for many tire manufacturers to optimize the inventive method for application with their own tires by performing the corresponding evaluation module with training data on training vehicle tires from a corresponding tire manufacturer, which often exhibit greater similarities with regard to the structural designs, the tread patterns and / or the rubber materials used, thus facilitating machine learning-based evaluation.

[0046] A further advantageous embodiment of the method according to the invention can be achieved in particular by evaluating the profile condition against the background of information about the initial state of the vehicle tire's profile. This information may, for example, include details about the initial tread depth or the roughness of the surface rubber material.

[0047] Knowing the initial condition allows for an assessment of the extent of deterioration when evaluating the tread condition, for example, as a difference compared to the initial state. This makes it easier to identify specific wear phenomena, such as uneven wear or disproportionately rapid wear relative to the tire's age and / or mileage. To this end, the inventors propose that the condition assessment device be equipped with means by which it can identify the tire type of the vehicle tire to be evaluated with regard to its tread condition using the inventive method. Based on the tire type thus determined, tread information can then be retrieved and used as the basis for, and / or considered in, the evaluation in process step c).

[0048] In this background, a method according to the invention is preferred, wherein the method additionally includes the process step a0): a0) Identifying the tire type of a vehicle tire using an identification unit of the condition assessment device, wherein the evaluation of the profile condition in process step c) is carried out by correlating the acquired first graphical representation and the acquired second graphical representation with at least one profile information associated with the identified tire type regarding the macroscopic surface texture and / or the microscopic surface texture. A method according to the invention is particularly preferred in which the profile information associated with the identified tire type of the vehicle tire is stored on the storage unit.

[0049] The tread pattern information associated with the tire type, which is used to correlate the condition of the tread section, depends, in accordance with expert understanding, significantly on the type of surface texture detected. For example, if, in a particularly simple example, the detected macroscopic surface texture relates to the remaining tread depth of a groove, the tread pattern information used could consist of geometric reference data of the original tread pattern, i.e., the initial groove depth, so that, through correlation, it can be determined how much the tread depth has already been reduced.The person skilled in the art understands that, advantageously, more and more information can be obtained starting from this simple scenario, for example, if the detected surface texture includes multiple pieces of information about the tread depth at several points, each of which can be compared with geometric reference data. A preferred method according to the invention is therefore one in which the tread information associated with the identified tire type of the vehicle tire is selected from the group consisting of geometric reference data of the initial tread, in particular regarding tread depths and tread structures, three-dimensional images of the initial tread, and topographic representations of the initial tread.

[0050] The inventors of the present invention propose, firstly, that the identification unit could be, for example, an electronic reading unit that can read RFID chips arranged in the vehicle tire, or that can access information recorded on the tire by means of a QR code, the latter being regularly accomplished using an optical image capture device. The advantage here is that this form of reading regularly enables particularly reliable identification of the tire type and is less prone to misinterpretations than more complex, image-based methods, such as those disclosed below.It is also advantageous that the corresponding functionalities of the identification unit can be regularly provided via typical electronic end devices, for example, mobile phones which have corresponding readers, and thus identification is easily possible for the end user. A preferred method according to the invention is therefore one in which the identification unit comprises an electronic reading unit configured to read an electronic identification element arranged in the vehicle tire, preferably an RFID or NFC element, particularly preferably an RFID element, or a marking element arranged on the vehicle tire, preferably a QR code or a barcode, in order to identify the tire type via information readable from the identification element or marking element.

[0051] However, the inventors believe that a disadvantage of using an electronic reading unit is that it requires the presence of corresponding readable elements in or on the vehicle tire. Accordingly, the inventors have designed an identification unit that eliminates this requirement and thus enables the reliable identification of vehicle tires, even if the tire lacks identification and / or marking elements. Specifically, the inventors propose using an optical image capture device, such as a mobile phone camera, to take an image of the vehicle tire, particularly its characteristic tread pattern, and then automatically assigning this image to a tire type using an electronic data processing device.Those skilled in the art understand that, particularly when identification is based on parts of the vehicle tire other than the tread pattern, this image-based evaluation will usually rely on other identifying elements, such as the lettering on the sidewall. In this respect, there is some overlap with the use of identification elements such as QR codes described above. A preferred method according to the invention is therefore one in which the identification unit comprises an optical image capture device, wherein the identification in process step a0) comprises generating an image of the vehicle tire, preferably a section of the tire's tread, with the optical image capture device, and wherein the electronic data processing device is configured to identify the tire type of the vehicle tire based on the generated image of the vehicle tire.

[0052] The inventors believe that the function described above, namely the identification of the tire type from the generated image of the vehicle tire, can be carried out in different ways, with various software solutions available on the market, for example for so-called "pattern recognition", which the person skilled in the art uses depending on the functionality he or she wants to achieve or which he or she adapts to the respective requirements of the application.

[0053] One possibility is to compare the generated image with images of possible vehicle tire types stored in the memory unit. According to the inventors, this is particularly advantageous in terms of storage requirements and computing power when the possible variety of tire types is low. A method according to the invention is therefore conceivable in which the electronic data processing device is configured to identify the tire type of the vehicle tire by comparing the generated image with a large number of images of vehicle tires of different types stored in the memory unit.

[0054] However, the inventors consider a method that uses machine learning for identification to be preferred for most embodiments. For this purpose, an identification module is provided in the storage unit, which the electronic data processing device uses to evaluate the generated image of the vehicle tire.A preferred method according to the invention is therefore one in which a machine learning-based identification module is stored on the storage unit, wherein the electronic data processing device is configured to provide the generated image of the vehicle tire as input to the identification module and to identify the tire type of the vehicle tire based on the generated image of the vehicle tire, wherein the identification module is trained to identify the tire type of the vehicle tire from the image of the vehicle tire, wherein the training is carried out with a set of training data which comprises a plurality of images of vehicle tires, preferably images of profile sections of vehicle tires, with different tire types.

[0055] Regardless of how the status information is ultimately obtained in process step c), it can, for example, either be further processed in downstream computer-implemented procedures, or – presumably particularly relevant in practice – be issued directly to the vehicle drivers or fleet operators.

[0056] A method according to the invention is therefore also preferred, additionally comprising the process step: d) Outputting the received status information via an output unit of the status assessment device.

[0057] In process step d), the result of the correlation, i.e., the condition information, is output by the condition assessment device. Regarding the manner of this output, there is a wide range of possibilities, which depend in particular on the level of detail of information to be provided to the user in the inventive method. In the simplest embodiment, for example, it would be conceivable that the output of the condition information is limited to indicating that a tire change is necessary. In this case, it is an inventive method in which the output of the condition information includes the output of a warning message regarding a necessary tire change and / or a necessary configuration change on the vehicle.

[0058] Even though the output could theoretically be provided, for example, by a beep, it is preferable for user acceptance in essentially all embodiments if the status information is at least partially displayed visually, for example, via a display. The level of detail in the output status information varies depending on the complexity of the detected surface topography and the result of the resulting correlation of the profile information. A method according to the invention is preferred for this purpose, wherein the output unit comprises a display.

[0059] If, as disclosed above, the corresponding graphical representations for the vehicle tire are recorded and compared with stored profile information in particularly preferred methods, it is especially preferred to also output this highly detailed information as condition information. According to the inventors, there are advantageously numerous display options that also provide untrained end users with a clear understanding of how to assess the condition of the examined vehicle tire, for example, by graphically overlaying the detected surface properties with the original surface properties and / or by displaying a difference representation that can, for example, use color coding to illustrate in which areas excessive wear has been observed, such as by color-coding these areas with a warning color.A preferred method according to the invention is therefore one in which the output of the status information comprises the output of a three-dimensional image of the first profile section and / or a topographic representation of the first profile section.

[0060] In addition to considering information about the initial condition of the vehicle tires, the evaluation of the tread condition in process step c) can be made more efficient by also taking further tire information into account. This additional input allows for an even more reliable evaluation in a data-driven approach, particularly when using machine learning. Specifically, considering historical tire information allows conclusions to be drawn about whether the condition information obtained by evaluating the vehicle tire's tread condition corresponds, at least roughly, to expectations. A deviation can advantageously serve as an early indicator of a potential problem, for example, with the vehicle tire itself or with the vehicle equipped with it, such as its suspension settings.Furthermore, considering current tire information, particularly regarding tire pressure and axle load, makes it possible, for example, to take into account any effects of tire deformation when evaluating the graphical representations. A preferred method according to the invention therefore additionally comprises the following process step prior to process step c): b0) Determining or providing one or more additional tire information pieces, wherein the evaluation of the profile condition of the vehicle tire in process step c) is carried out taking into account one or more additional tire information, wherein the condition information preferably includes information about the deviation from the condition expected taking into account the additional tire information.

[0061] A method according to the invention is particularly preferred, wherein the further tire information is selected from the group consisting of historical tire information and current tire information.

[0062] A particularly preferred method according to the invention is one in which the historical tire information is selected from the group consisting of the tire age, the mileage completed in the past, preferably including the route and its characteristics, the wheel load experienced in the past, the tire pressure prevailing in the past, the vehicles operated with the vehicle tire in the past, including their drive type, and the axle position assumed in the past.

[0063] Particularly preferred is, additionally or alternatively, a method according to the invention in which the current tire information is selected from the group consisting of the current wheel load, the current prevailing tire pressure, the vehicle currently operated with the vehicle tire, including its drive type, and the currently assumed axle position.

[0064] The invention also relates to a condition assessment device for use in a method according to the invention, comprising i) an electronic data processing device with a storage unit, ii) a first detection unit for capturing a first graphical representation of the macroscopic surface texture for at least a first profile section of the vehicle tire, wherein the first detection unit uses an optical detection method, iii) a second detection unit for capturing a second graphical representation of the microscopic surface texture for at least a second profile section of the vehicle tire, wherein the second detection unit uses an acoustic detection method, wherein the electronic data processing device is configured to evaluate the profile condition of the vehicle tire by evaluating the first graphical representation and the second graphical representation.

[0065] The invention and preferred embodiments of the invention are explained and described in more detail below with reference to the accompanying figures. These figures show: Fig. 1 a schematic flowchart of the inventive method for evaluating the profile condition of vehicle tires; Fig. 2 a schematic representation of a preferred condition assessment device according to the invention for use in a method according to the invention; and Fig. 3 a schematic representation of the condition assessment device according to the invention Fig. 2 in use in a preferred method according to the invention at different times.

[0066] Fig. Figure 1 schematically shows the process of an inventive method for evaluating the profile condition of vehicle tires 10 with an electronic condition assessment device 12 in a preferred embodiment.

[0067] As in Fig. As shown in Figure 2, the condition assessment device 12, designed as a mobile phone, comprises an electronic data processing device 14 with a storage unit 16 and a machine learning-based assessment module 34 stored therein. Furthermore, the condition assessment device 12 includes a first detection unit 20 with an optical image acquisition device 28 and a projection device 30, as well as a second detection unit 24, distinct from the first detection unit 20, with an ultrasonic sensor 32. The condition assessment device 12 also includes an identification unit 26 and an output unit 36 ​​designed as a display.

[0068] In the described process, the tire type of the vehicle tire 10 is first identified in a preliminary step 100 using the identification unit 26. The tire type is identified, for example, by an electronic reading unit or an optical image capture device of the identification unit 26.

[0069] The electronic reading unit can, for example, read an RFID element or a QR code / barcode on the vehicle tire 10, which contains information about the tire type or manufacturer. Alternatively or additionally, the optical image capture device can also capture an image of the tread of the vehicle tire 10, which is evaluated by the data processing device 14 to identify the tire type. This evaluation can be carried out, for example, by comparing the generated image with images of vehicle tires 10 of different tire types stored in the storage unit 16. In the example shown, this is specifically implemented using a machine learning-based identification module stored on the storage unit 16, which is trained on a set of training data to identify the tire type of the vehicle tire 10 based on the generated image.

[0070] In a further process step 102, the first detection unit 20 of the condition assessment device 12 is used to acquire a first graphical representation of the macroscopic surface texture for at least a first profile section 18 of the vehicle tire 10 by means of an optical detection method. For this purpose, the first detection unit 20 uses the optical image acquisition device 28, wherein in the example shown the Fig. 2 the optical image acquisition device 28 of the first detection unit 20 and the optical image acquisition device of the identification unit 26 are formed by the same optical image acquisition device, which in the example shown is designed as the camera of the mobile phone, so that the identification of the tire type in the example shown can advantageously be carried out directly on the basis of the macroscopic surface texture in the first profile section 18, which is already recorded.

[0071] A schematic representation of the combined process steps 100 and 102 in a particularly preferred embodiment is shown in Fig. 3a) shown. In the example shown, the optical image acquisition device 28 captures an image of the profile structure in the first profile section 18 using the optical detection method, so that the electronic data processing device 14 can calculate a three-dimensional representation of the macroscopic surface texture from the images, on which structural elements with a dimension of 5 mm or more can be recognized.

[0072] In the example shown, a projection device 30 is used, by means of which a point cloud is projected onto the first profile section 18 of the vehicle tire 10 using IR radiation, the distortion of which is detected by the image acquisition device 28 promotes the acquisition of the first graphic representation of the first profile section 18 as a three-dimensional representation.

[0073] In a further process step 104, the second detection unit 24 of the condition assessment device 12 is used to acquire a second graphical representation of the microscopic surface texture for at least a second profile section 22 of the vehicle tire 10 by means of an acoustic detection method. For this purpose, the second detection unit 24 uses the ultrasonic sensor 32 of the mobile phone, which is originally intended for fingerprint acquisition.

[0074] A schematic representation of process step 104 in a particularly preferred embodiment is shown in Fig. 3b) shown. Here, the condition assessment device 12 is placed on the second profile section 22, whereby the quality of the signals received from the ultrasonic sensor 32 can be improved, for example, by means of a measuring gel applied at the contact point. In the example shown, the ultrasonic sensor 32 emits ultrasonic pulses and receives the reflected sound pulses, so that the electronic data processing device 14 can calculate a two-dimensional representation of the microscopic surface texture from the signals, i.e., a graphic image of the second profile section 22, in which height information can be recognized, for example, via contained color information. In this way, the surface roughness of the second profile section 22 as well as microcracks, i.e., structural elements with a dimension of 0.5 mm or less, can be detected. In the example shown, the Fig. 3 a) and b) the second profile section 22 is completely encompassed by the first profile section 18.

[0075] In a further process step 106, several additional tire information points are provided, such as historical tire information like the tire age, past mileage, and past tire pressure. Alternatively or additionally, current tire information such as the current wheel load and current tire pressure is also determined.

[0076] In a further process step 108, the condition of the vehicle tire 10 is then evaluated by evaluating the first graphic representation and the second graphic representation with the electronic data processing device 14 via the evaluation module 34, which is based on machine learning.

[0077] The evaluation is performed by correlating the captured first graphical representation with the captured second graphical representation to obtain status information. This status information also includes, for example, information about the deviation from the expected state, taking into account the other tire information.

[0078] For this purpose, the evaluation module 34 is trained to evaluate the profile condition of the vehicle tire 10 based on the recorded first graphic representation of the macroscopic surface texture and the recorded second graphic representation of the microscopic surface texture, whereby the training of the evaluation module 34 can be carried out as disclosed above.

[0079] In a final step 110, the received status information, for example a graphically processed three-dimensional image of the first profile section 18 or a colored topographic representation of the first profile section 18, is output via the output unit 36 ​​of the condition assessment device 12. In the example shown, the Fig. 3. This includes, for example, issuing a warning about a necessary tire change and a necessary configuration change to the vehicle. Reference symbol list 10 vehicle tires 12 Condition assessment device 14 Data processing device 16 storage units 18 first profile section 20 first detection unit 22 second profile section 24 second detection unit 26 Identification unit 28 optical image capture device 30 Projection device 32 Ultrasonic sensor 34 Assessment module 36 output units 100 Procedure step a0) 102 Procedure step a) 104 Procedure step b) 106 Procedure step b0) 108 Procedure step c) 110 Procedure step d)

Claims

[1] Method for assessing the profile condition of vehicle tires (10), comprising an electronic condition assessment device (12), comprising an electronic data processing device (14) with a storage unit (16), comprising the method steps: a) Capturing a first graphical representation of the macroscopic surface texture for at least a first profile section (18) of the vehicle tire (10) with a first detection unit (20) of the condition assessment device (12), wherein the first detection unit (20) uses an optical detection method, b) Capturing a second graphical representation of the microscopic surface texture for at least a second profile section (22) of the vehicle tire (10) with a second detection unit (24) of the condition assessment device (12) different from the first detection unit (20), wherein the second detection unit (24) uses an acoustic detection method, and c) Evaluating the profile condition of the vehicle tire (10) by evaluating the first graphical representation and the second graphical representation with the electronic data processing device (14) to obtain condition information. [2] The method of claim 1, wherein the method additionally comprises the process step a0): a0) Identifying the tire type of a vehicle tire (10) with an identification unit (26) of the condition assessment device (12), wherein the evaluation of the profile condition in process step c) is carried out by correlating the recorded first graphic representation and the recorded second graphic representation with at least one profile information linked to the identified tire type via the macroscopic surface texture and / or the microscopic surface texture. [3] Method according to one of claims 1 or 2, wherein the first graphic representation reveals macroscopic surface texture and structural elements with a dimension of 5 mm or more. [4] Method according to any one of claims 1 to 3, wherein the first detection unit (20) comprises an optical image acquisition device (28) and a projection device (30) which is configured to project a pattern onto the first profile section (18) of the vehicle tire (10), wherein the electronic data processing device (14) is configured to calculate a three-dimensional image and / or a topographic representation of the first profile section (18) of the vehicle tire (10) as a first graphic representation of the macroscopic surface texture from the image of the pattern detected by the first detection unit (20) on the first profile section (18) of the vehicle tire (10). [5] Method according to any one of claims 1 to 4, wherein the second detection unit (24) comprises an ultrasonic sensor (32). [6] Method according to any one of claims 1 to 5, wherein the electronic condition assessment device (12) directly or indirectly contacts the second profile section (22) in method step b). [7] Method according to any one of claims 1 to 6, wherein the second graphic representation reveals microscopic surface texture structural elements with a dimension of 0.5 mm or less. [8] Method according to any one of claims 1 to 7, wherein the second profile section (22) is at least partially encompassed by the first profile section (20). [9] Method according to any one of claims 1 to 8, wherein a machine learning-based evaluation module (34) is stored on the storage unit (16), wherein the electronic data processing device (14) is configured to provide the captured first graphic representation and the captured second graphic representation as input to the evaluation module (34) and to evaluate the profile state based on the captured first graphic representation and the captured second graphic representation, wherein the evaluation module (34) is trained to evaluate the profile condition from graphical representations of the macroscopic surface texture, which were acquired using an optical detection method, and graphical representations of the microscopic surface texture, which were acquired using an acoustic detection method, where the training is carried out with a set of training data which includes a variety of graphical representations of the macroscopic surface texture, which were captured by an optical detection method, and graphical representations of the microscopic surface texture, which were captured by an acoustic detection method, of training vehicle tires with different, known tread conditions. [10] Condition assessment device (12) for use in a method according to any one of claims 1 to 9, comprising i) an electronic data processing device (14) with a storage unit (16), ii) a first detection unit (20) for capturing a first graphical representation of the macroscopic surface texture for at least a first profile section (18) of the vehicle tire (10), wherein the first detection unit (20) uses an optical detection method, iii) a second detection unit (24) for capturing a second graphical representation of the microscopic surface texture for at least a second profile section (22) of the vehicle tire (10), wherein the second detection unit (24) uses an acoustic detection method, wherein the electronic data processing device (14) is configured to evaluate the profile condition of the vehicle tire (10) by evaluating the first graphical representation and the second graphical representation.

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